Electrode control fob abc furnaces



Filed May 1926 Patented July 5, 1927.

UNITED STATES THADDEUS F. BAILY, 01: ALLIANCE, OHIO.

ELECTRODE CONTROL FOR ARC FURNACES.

Application tiled May 24, 1926.

in the present types of automatic are farnace control apparatus. such as are in common use, the. movement. of the electrode accomplished by a motor which in lu'rn'lS controlled by some current control device operating relays which in turn'cont'rol the movement of the motor and hence the electrode.

The disadvantage of the aforcim-ntii'mwl type of control is that an appreciable delay elapses between the time overload or underload condition is developed in the furnace and the time that the corrective measures are applied. r

The object of the present. type of equipment is to provide a means that is almost instantaneous or selectively, timed in its action for correcting any variation in the power iii-put to the furnace and this is accomplished by placing a powerful magnet directly onto the iiiast mechanism or'elec trode holder 'to which one ol the electrodes is attached. It will further he noted tnat while this magnet has a limited range sullicient. however,

"fluctuations in the current. the equipment.

described is provided with means for taking I care of any required variations by means of an automatic switch which is operated by the movement of the mast. ur holder on which the magnet armature is attached, so that when the magnet, in controlling the currenthas reached nearly its extreme travel in either direction beyond which it is.

no longer fully able to control the current supplied to the electrode, it will operate a reversible switch, controllinglhe motor for operatin the entire mast. arm mechanism raising the outer sleeve of the electrode mast end on which the magnet stator is rigidly attached, thus-again bringing the imiinelectrode mast into its central position.

It, will further be noted that in one arrangement of the present, invention, the electrode mast proper is floated at; its upper end on a sprin the lower end of which rests on the electrode mast sleeve before mentioned, the weight of the mast mechanism proper and electrodes normally depressing this springso that, the ar -uature of the magnet is in its highest position when the maximum amount of current is flowing to the coils of the magnet. The armature is thus pulled down depressing the spring until current flows from electrode to electrode, and,

to take care of any normal Serial No. 111,437.

it more power than isdesired flows between electrodes. then the current flowing to the' magnet coils is decreased and the strength of the magnet pull lessened until the spring has pulled the elect-rode sutiiciently far apart to maintain the correct current flow.

The amount of current flowing to the coil of the magnet is controlled by means of a reactor coil composed of a loop of trans former steel laminae around which is wound a coil of insulated copper wire of the proper number of turns and cross-section and also one of the leads going to the electrodes .s passed through these laminae toproduce a dampening effect in the current.

One of the terminals of this coil is conncctcd to the. electrode and the other one goes to one terminal of the "magnet coil. The other end of the magnet coil is then ledto the other electrode.

An embodiment of the invention is illustrated in the. accompanying drawing, in which I The figureis a diagrammatic "low of an arc furnace provided with the impioved control apparatus.

Similar numerals refer to similar parts throughout the drawing.

The furnace is indicated generally at 1, and provided with the lower electrode 2, which may be stationary, and is connected by the cable 3 to any suitable source of electric power. A removable lid, orcovcr, 4 may be provided for the furnace. having the central opening 5, through which the movable electrode 6 is extended, said electrode being connected by the cable 7 to the same source of electric power.

The movable electrode may be suspended from the arm 8 supported at the upper end of the longitudinally movable mast or electrode support, 9, which may be slidablv movable within the tube 10 also slidably mounted within the bearing 11 carried at one side of the furnaoe.

The lower end of the tube 10- may be enlarged, as at- 1, forming a casing for the magnet coil 13 connected as by the wires 14 and 15 to the cables 3 and 7 respectively. The wire 14 is preferauiy connected to a coil 16 wound around core 17 of a reactor, tended through the core.

The armature 18 is carried by he must the cable 3 being exhollow center of said the laminated iron not armature is 9 and extended throu h thecoil or stator 13 of the m et an a coil spring 19 ,is connected to t e upper end of the mast, and interposed between the same and the upper end of the sliding tubelO, and is arranged to work against the pull of the magnet to tend to raise the mast 9, and-with it the electrode 6, while the magnet tends to lower the same.

' The magnet coil, orstator and tube 10 are arranged to he longitudinally movedwithin the guide 11 as by the cables'20 and drums 21. Eachof these drums1 may be provided with=a'worm gear 22 engaged by aworm 23, upon theshatt 24jo the rev-enain motor25, a I in the drawinga three phasamotor is illustrated although it will be understood that this is' not essehtialgf Current is suplied to this motor through-thewires 26- ending power,

from any suitable source of electric such as indicated 'at 27, a reversible switch 28 being located in the motor circuit and being r'ovide'd with a handle 29, engaged by a 00 -30 upon themast'9 or arma= ture 18, where y movement of the mast relative to the tube be operated, it 4 switch is carried by, or fixed with relation to, the tube 10 and magnet coil 13. a

In starting the operation of this control equipment with the electrodes so far apart that the pull of the magnet may not be such as to draw au-arc between the electrodes, the

armature 18 of the magnet will be so far depressed as to throw the automatic reversible switch 28- into its lower position, therefore making contact with the electrode moving motor 25 so that the entire mast 9 and tube 10 descends until an arc isestablishedlbetween electrodes.

The instant that this like is established'the' current flowing to the magnet coils 13 is reduced, due to the bucking effectof the rushing current through the main "leads afleeting the windings ionthe reactor coil 1-1, and since 'the pulling effect or the magnet is therefore reduced the sprin 19 -is' able to raise the must 9 and upper e ectrode a sufiicient distance, underl'norma'l conditions, to steady the arc.

However, under abnormal conditions, if this upward movement caused by the magnet isnot snfiicient to fully control the current, the armature of the magnet having reachedits'upper position it throws the motor control switch in-the reverse position, to

that previously mentioned, and the motorfor operating the mast mechanism raises the entire mast until the current flowing in the min are circuit has become normal.

During this upward movenfient the magadinsting itse f with reference to the co 6 and when the normal relation 0 those two is efieeted their trode maybe controlled by 1 will cause the switch 28 to eing understood that this relative position is such as to put the motor control switch in" .its neutral position and sto the motor.

' do not wish to be limited to the shuntarrangement shown in the drawing, as this may be a series connection or a combination of shunt and series connection, for connecting the ma et with the electrodes; and also I wish to ave it understood that the eleca counterweight or partly by a counterweight and partly by the spring.

The magnet performs two duties,

mature and statoracts like "a reactor of full iron core, therefore balancing andmaintainin a steady even current' fiow,

claim 1; An electrode control for areiurnaces including a longitudinally movable. elect-rode support, means for moving said support lon- 'tudinally, mg means .and. a magnetoperatively connected to the sup rt for controlling the closer. regulation 0 the support.

2. An electrode control for are furnaces including a longitudinally'movahle electrode support, means for moving said support longitudinally, a motor controlling said movg means and 'a magnet operatively con nected to the support for controllin the closer regulation of the support an the movement of the support controlling the operation of the motor. x I 3. An 'electrode control for are furnaces including a longitudinally movable tube, a magnet stator" carried thereby, a mast lon gitudinally movable within said tube, a mag net armature carried by the mast and cm operating with the stator, an electrode suported by the mast, means 'for normally urging the mast upward in the tube, a reversing motor for longitudinally moving the magnet stator and tube and means controlled by the movement of the mast for controlling the movement of the motor, Y I

4. An electrodecontrol for are furnaces including a longitudinally "movable tube, a magnet stator carried thereby, a mast longitudinally movable Within "said tube, a magnet armature carried by the mast and co operating with the stator, an electrode supported by the mast, spring means fornor mally-urging the mast upward in the'tube, a reversing motor for ion itudinally moving the magnet stator and tu and means controlled y the movement of the mast for controlling the movement of themotor. 5. electrode control for are furnaces including a -;longitudinally movable mast, an electrode carried thereby, a motor for longitudinally moving the mast, an'electi omag-v net for moving t e mast independently of the motor. the movement of the motor be that is by pulling apart the electrodes it buildsthe are distance and by its especially shaped ar-' a motor controlling said moy-Y ing controlled by the movement of the mag net armature.

6. An electrode control for are furnaces including a movable electrode support, an electrode carried thereby, a motor for moving the support, an electro-magnet for mov ing the support independently of the motor, the movement of the motor being controlled by the magnet.

7. An electrode control for are furnaces including a movable electrode support, an electrode carried thereby, a motor for moving the support, an electro-magnet for moving the support independently of the motor, the movement of the motor being controlled by the movement of the magnet.

8. An electrode control for are furnaces including a movable electrode sup ort, an electrode carried thereby, a motor or moving the support, an electro-rnagnet for moving the support independently of the motor,

' the movement of the motor being controlled by the movement of the magnet armature.

9. An electrode control for are furnaces including a movable electrode support, a magnet operatively associated with the su port and arranged to move the support wit 10. An electrode control for arc furnaces 1 including a movable electrode support, a magnet operatively associated with the support and arranged to move the support within predetermined limits and a motor operatively associated with the support and arranged to move the support beyond the limit of movement by the magnet, the operation of the motor being controlled by the magnet.

1L An electrode control for are furnaces including a movable electrode support, a magnet operatively associated with the support and arranged to move the support within predetermined limits and a motor operat-ively associated with the support and arranged to move the support beyond the limit of movement by the magnet, the operation of the motor being controlled by the move ment of the support.

In testimony that I claim the above, I have hereunto subscribed myname.

THADDEUS F. BAILY. 

